its well known that intellisense has always been broken with things like ListList.Contains or pressing . after typing certain prefixes does not correctly show options, or typing null enter put...
They do have Intellisense for M / Power Query, but it is as buggy as a trucker's windshield. I tried to bring this up at the Community Forum but not getting a lot of traction:
Power Query Intellisense not working well - Microsoft Power BI Community
Power Query Intellisense not working well - Microsoft Power BI Community
